2002 JEEP LIBERTY Workshop Manual

(4) Install flex plate. Apply MopartLock & Seal
Adhesive to bolt threads and tighten bolts to 95 N´m
(70 ft. lbs.).
(5) Install the transmission.
PISTON & CONNECTING ROD
DESCRIPTION
The pistons are made of a cast aluminum alloy.
The pistons have pressed-in pins attached to forged
powdered metal connecting rods. The pistons pin is
offset 1 mm (0.0394 in.) towards the thrust side of
the piston. The connecting rods are a cracked cap
design and are not repairable. Hex head cap screws
are used to provide alignment and durability in the
assembly. The pistons and connecting rods are ser-
viced as an assembly.
OPERATION
The piston and connecting rod is the link between
the combustion force to the crankshaft.
REMOVAL
NOTE: Cylinder Head must be removed before Pis-
tons and Rods. Refer to Cylinder Head Removal in
this section.
(1) Remove top ridge of cylinder bores with a reli-
able ridge reamer before removing pistons from cyl-
inder block.Be sure to keep tops of pistons
covered during this operation. Mark piston with
matching cylinder number (Fig. 60).
(2) Remove oil pan. Scribe the cylinder number on
the side of the rod and cap (Fig. 61) for identification.
(3) Pistons have a directional stamping in the
front half of the piston facing towards thefrontof
engine.
(4) Pistons and connecting rods must be removed
from top of cylinder block. Rotate crankshaft so that
each connecting rod is centered in cylinder bore.
(5) Remove Balance Shaft Assembly. Refer to Bal-
ance Shaft Removal in this section.
(6) Remove connecting rod cap bolts. Push each
piston and rod assembly out of cylinder bore.
NOTE: Be careful not to nick crankshaft journals.
(7) After removal, install bearing cap on the mat-
ing rod.
(8) Piston and Rods are serviced as an assembly.
Fig. 59 Rear Crankshaft SealÐInstallation
1 - SPECIAL TOOL 6926±2 INSTALLER
Fig. 60 Piston Markings
1 - DIRECTIONAL ARROW WILL BE IMPRINTED IN THIS AREA
9s - 40 ENGINEKJ
CRANKSHAFT OIL SEAL - REAR (Continued)

INSTALLATION
(1) Before installing pistons and connecting rod
assemblies into the bore, be sure that compression
ring gaps are staggered so that neither is in line with
oil ring rail gap.
(2) Before installing the ring compressor, make
sure the oil ring expander ends are butted and the
rail gaps located as shown in (Fig. 62). As viewed
from top.
(3) Immerse the piston head and rings in clean
engine oil, slide the ring compressor, over the piston
(Fig. 63).Be sure position of rings does not
change during this operation.
(4) The directional stamp on the piston should face
toward the front of the engine.
(5) Rotate crankshaft so that the connecting rod
journal is on the center of the cylinder bore. Insert
rod and piston assembly into cylinder bore and guide
rod over the crankshaft journal.(6) Tap the piston down in cylinder bore, using a
hammer handle. At the same time, guide connecting
rod into position on connecting rod journal.
NOTE: The connecting rod cap bolts should not be
reused.
(7) Before installing theNEWbolts the threads
should be coated with clean engine oil.
(8) Install each bolt finger tight than alternately
torque each bolt to assemble the cap properly.
CAUTION: Do not use a torque wrench for second
part of last step.
(9) Tighten the bolts to 54 N´m PLUS 1/4 turn (40
ft. lbs. PLUS 1/4 turn).
(10) Using a feeler gauge, check connecting rod
side clearance (Fig. 64).
Fig. 61 Identify Connecting Rod to Cylinder
Fig. 62 Piston Ring End Gap Position
1 - GAP OF LOWER SIDE RAIL
2 - NO. 1 RING GAP
3 - GAP OF UPPER SIDE RAIL
4 - NO. 2 RING GAP AND SPACER EXPANDER GAP
Fig. 63 PistonÐInstallation
Fig. 64 Checking Connecting Rod Side Clearance
KJENGINE9s-41
PISTON & CONNECTING ROD (Continued)

PISTON RINGS
STANDARD PROCEDURE
PISTON RING - FITTING
(1) Wipe cylinder bore clean. Insert ring and push
down with piston to ensure it is square in bore. The
ring gap measurement must be made with the ring
positioning at least 12 mm (0.50 inch) from bottom of
cylinder bore. Check gap with feeler gauge (Fig. 65).
Refer to Engine Specifications.
(2) Check piston ring to groove side clearance (Fig.
66). Refer to Engine Specifications.
PISTON RINGS - INSTALLATION
(1) Install rings with manufacturers I.D. mark fac-
ing up, to the top of the piston (Fig. 67).
CAUTION: Install piston rings in the following
order:
a. Oil ring expander.
b. Upper oil ring side rail.
c. Lower oil ring side rail.
d. No. 2 Intermediate piston ring.
e. No. 1 Upper piston ring.
(2) Install the side rail by placing one end
between the piston ring groove and the expander.
Hold end firmly and press down the portion to be
installed until side rail is in position.Do not use a
piston ring expander(Fig. 68).
(3) Install upper side rail first and then the lower
side rail.
(4) Install No. 2 piston ring and then No. 1 piston
ring.
(5) Position piston ring end gaps as shown in (Fig.
69).
(6) Position oil ring expander gap at least 45É
from the side rail gaps butnoton the piston pin cen-
ter or on the thrust direction. Staggering ring gap is
important for oil control.
Fig. 65 Piston Ring Gap
1 - FEELER GAUGE
Fig. 66 Piston Ring Side Clearance
1 - FEELER GAUGE
Fig. 67 Piston Ring Installation
1 - NO. 1 PISTON RING
2 - NO. 2 PISTON RING
3 - SIDE RAIL
4 - OIL RING
5 - SPACER EXPANDER
9s - 42 ENGINEKJ

VIBRATION DAMPER
REMOVAL
(1) Remove accesory drive belts. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL)
(2) Remove crankshaft damper bolt.
(3) Remove damper using Special Tool 3-Jaw
Puller 1026 and Insert 6827±A (Fig. 70).
INSTALLATION
(1) Install crankshaft vibration damper using M12
1.75 x 150 mm bolt, washer, thrust bearing and nut
from Special Tool 6792 (Fig. 71).
(2) Install crankshaft vibration damper bolt and
tighten to 142 N´m (105 ft. lbs.).
(3) Install accessory drive belts. (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION)
Fig. 68 Installing Side Rail - Typical
1 - SIDE RAIL END
Fig. 69 Piston
1 - GAP OF LOWER SIDE RAIL
2 - NO. 1 RING GAP
3 - GAP OF UPPER SIDE RAIL
4 - NO. 2 RING GAP AND SPACER EXPANDER GAP
Fig. 70 Crankshaft Vibration Damper - Removal -
Typical
1 - SPECIAL TOOL 1026 3-JAW PULLER
2 - SPECIAL TOOL 6827±A INSERT
Fig. 71 Crankshaft Vibration Damper - Installation -
Typical
1 - M12±1.75 ý 150 MM BOLT, WASHER AND THRUST BEARING
FROM SPECIAL TOOL 6792
KJENGINE9s-43
PISTON RINGS (Continued)

STRUCTURAL COLLAR
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove structural collar attaching bolts.
(3) Remove collar.
INSTALLATION
CAUTION: Torque procedure for the structural collar
must be followed or damage could occur to oil pan
and collar.
(1) Perform the following steps for installing struc-
tural collar.
²Step 1: Position collar between transmission and
oil pan. Install collar to transmission bolts,hand
start only.
²Step 2: Install collar to oil pan bolts,hand snug
only.
²Step 3: Tighten collar to transmission bolts.
²Step 4: Tighten collar to oil pan bolts.
(2) Lower vehicle.
ENGINE MOUNTING
DESCRIPTION
The engine mounting system consist of three
mounts; right and a left side support the powertrain,
and rear mount to control powertrain torque. The
mounts are of molded rubber material.
FRONT MOUNT
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove the front engine mount through bolt
from the insulator.
(3) Remove the engine front mount bolts and
remove the insulator assembly.
(4) Remove the front mounting bracket from
engine, if necessary.
INSTALLATION
(1) Install the insulator mount assembly (Fig.
72)and (Fig. 73).
(2) Tighten the mount to engine bolts.
(3) Loosely install the front engine mount through
bolt to the insulator.
(4) Lower the engine.
(5) Tighten the through bolt.
(6) Lower the vehicle.
Fig. 72 LH ENGINE MOUNT
1 - ENGINE MOUNT
2 - ENGINE MOUNT BOLT (3)
3 - ENGINE MOUNT THROUGH BOLT
Fig. 73 RH ENGINE MOUNT
1 - ENGINE MOUNT BOLT (4)
2 - ENGINE MOUNT THROUGH BOLT
3 - ENGINE MOUNT
9s - 44 ENGINEKJ

REAR MOUNT
REMOVAL
NOTE: A resilient rubber cushion supports the
transmission at the rear between the transmission
extension housing and the rear support crossmem-
ber or skid plate.
(1) Disconnect negative cable from battery.
(2) Raise the vehicle and support the transmission.
(3) Remove the nuts holding the support cushion
to the crossmember. Remove the crossmember.
MANUAL TRANSMISSION
a. Remove the support cushion nuts and remove
the cushion.
b. Remove the transmission support bracket bolts
and remove the bracket from the transmission.
AUTOMATIC TRANSMISSION
c. Remove the support cushion bolts and remove
the cushion and the support bracket from the trans-
mission (4WD) or from the adaptor bracket (2WD).
d. On 2WD vehicles, remove the bolts holding the
transmission support adaptor bracket to the trans-
mission. Remove the adaptor bracket.
INSTALLATION
MANUAL TRANSMISSION:
(1) Install the support cushion to the transmission
(Fig. 74)or (Fig. 75). Install the bolts and tighten.
(2) Position the crossmember in the vehicle. Install
the crossmember to mount through bolt and nut.
(3) Install crossmember-to-sill bolts and tighten to
41 N´m (30 ft. lbs.) torque.
(4) Remove the transmission support.
(5) Lower the vehicle.
(6) Connect negative cable to battery.
AUTOMATIC TRANSMISSION:
(1) Install the transmission mount to transmission
(Fig. 76) and (Fig. 77). Install the bolts.
(2) Position the crossmember in the vehicle. Install
the crossmember to mount through bolt and nut.
(3) Remove the transmission support.
(4) Lower the vehicle.
(5) Connect negative cable to battery.
Fig. 74 TRANSMISSION MOUNT-2.4L MANUAL
TRANS
1 - TRANSMISSION MOUNT
2 - MOUNTING BOLT
Fig. 75 TRANSMISSION MOUNT 3.7L MANUAL
TRANS 2WD
1 - NUT
2 - BOLT
3 - TRANS MOUNT
KJENGINE9s-45

LUBRICATION
DESCRIPTION
The lubrication system is a full-flow filtration,
pressure feed type. The oil pump is mounted in the
front engine cover and driven by the crankshaft.
OPERATION
Engine oil drawn up through the pickup tube and
is pressurized by the oil pump and routed through
the full-flow filter to the main oil gallery running the
length of the cylinder block. A diagonal hole in each
bulkhead feeds oil to each main bearing. Drilled pas-
sages within the crankshaft route oil from main bear-
ing journals to connecting rod journals. Balance shaft
lubrication is provided through an oil passage from
the number one main bearing cap through the bal-
ance shaft carrier support leg. This passage directly
supplies oil to the front bearings and internal
machined passages in the shafts that routes oil from
front to the rear shaft bearing journals. A vertical
hole at the number five bulkhead routes pressurized
oil through a restrictor (integral to the cylinder head
gasket) up past a cylinder head bolt to an oil gallery
running the length of the cylinder head. The cam-
shaft journals are partially slotted to allow a prede-
termined amount of pressurized oil to pass into the
bearing cap cavities. Lubrication of the camshaft
lobes are provided by small holes in the camshaft
bearing caps that are directed towards each lobe. Oil
returning to the pan from pressurized components
supplies lubrication to the valve stems. Cylinder
bores and wrist pins are splash lubricated from
directed slots on the connecting rod thrust collars.
DIAGNOSIS AND TESTING - ENGINE OIL
PRESSURE CHECKING
(1) Disconnect and remove oil pressure switch.
(Refer to 9 - ENGINE/LUBRICATION/OIL PRES-
SURE SENSOR/SWITCH - REMOVAL)
(2) Install Special Tools C-3292 Gauge with 8406
Adaptor fitting.
(3) Start engine and record oil pressure. Refer to
Specifications for correct oil pressure requirements.
(Refer to 9 - ENGINE - SPECIFICATIONS)
CAUTION: If oil pressure is 0 at idle, do not perform
the 3000 RPM test
(4) If oil pressure is 0 at idle. Shut off engine,
check for pressure relief valve stuck open, a clogged
oil pick-up screen or a damaged oil pick-up tube
O-ring.
(5) After test is complete, remove test gauge and
fitting.
Fig. 76 TRANSMISSION MOUNT 3.7L 2WD AUTO
TRANS
1 - BOLT
2 - MOUNT
Fig. 77 TRANSMISSION MOUNT 3.7L 4WD AUTO
TRANS
1 - MOUNT
2 - BOLT
9s - 46 ENGINEKJ
LUBRICATION (Continued)

(6) Install oil pressure switch and connector. (Refer
to 9 - ENGINE/LUBRICATION/OIL PRESSURE
SENSOR/SWITCH - INSTALLATION)
OIL
STANDARD PROCEDURE
ENGINE OIL LEVEL CHECK
The best time to check engine oil level is after it
has sat overnight, or if the engine has been running,
allow the engine to be shut off for at least 5 minutes
before checking oil level.
Checking the oil while the vehicle is on level
ground will improve the accuracy of the oil level
reading. Remove dipstick and observe oil level. Add
oil only when the level is at or below the ADD mark
(Fig. 78).
STANDARD PROCEDURE - ENGINE OIL AND
FILTER CHANGE
Change engine oil at mileage and time intervals
described in the Maintenance Schedule. (Refer to
LUBRICATION & MAINTENANCE/MAINTE-
NANCE SCHEDULES - DESCRIPTION)
WARNING: NEW OR USED ENGINE OIL CAN BE
IRRITATING TO THE SKIN. AVOID PROLONGED OR
REPEATED SKIN CONTACT WITH ENGINE OIL.
CONTAMINANTS IN USED ENGINE OIL, CAUSED BY
INTERNAL COMBUSTION, CAN BE HAZARDOUS TO
YOUR HEALTH. THOROUGHLY WASH EXPOSED
SKIN WITH SOAP AND WATER. DO NOT WASH
SKIN WITH GASOLINE, DIESEL FUEL, THINNER, OR
SOLVENTS, HEALTH PROBLEMS CAN RESULT. DO
NOT POLLUTE, DISPOSE OF USED ENGINE OIL
PROPERLY. CONTACT YOUR DEALER OR GOVERN-
MENT AGENCY FOR LOCATION OF COLLECTION
CENTER IN YOUR AREA.
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.(2) Hoist and support vehicle on safety stands.
Refer to Hoisting and Jacking Recommendations.
(Refer to LUBRICATION & MAINTENANCE/HOIST-
ING - STANDARD PROCEDURE)
(3) Remove oil fill cap.
(4) Place a suitable drain pan under crankcase
drain.
(5) Remove drain plug from crankcase and allow
oil to drain into pan. Inspect drain plug threads for
stretching or other damage. Replace drain plug and
gasket if damaged.
(6) Remove oil filter. (Refer to 9 - ENGINE/LUBRI-
CATION/OIL FILTER - REMOVAL)
(7) Install and tighten drain plug in crankcase.
(8) Install new oil filter. (Refer to 9 - ENGINE/LU-
BRICATION/OIL FILTER - INSTALLATION)
(9) Lower vehicle and fill crankcase with specified
type and amount of engine oil. (Refer to LUBRICA-
TION & MAINTENANCE/FLUID TYPES -
DESCRIPTION)
(10) Install oil fill cap.
(11) Start engine and inspect for leaks.
(12) Stop engine and inspect oil level.
NOTE: Care should be exercised when disposing
used engine oil after it has been drained from a
vehicle engine. Refer to the WARNING listed above.
OIL FILTER
DESCRIPTION
The engine oil filter is a high quality full-flow, dis-
posable type. Replace the oil filter with a Mopartor
the equivalent.
REMOVAL
(1) Raise vehicle on hoist.
(2) Position an oil collecting container under oil fil-
ter location.
CAUTION: When servicing the oil filter avoid
deforming the filter can by installing the remove/in-
stall tool band strap against the can to base lock
seam. The lock seam joining the can to the base is
reinforced by the base plate.
(3) Using a suitable filter wrench, turn oil filter
counterclockwise to remove (Fig. 79).
INSTALLATION
(1) Clean and check filter mounting surface. The
surface must be smooth, flat and free of debris or
pieces of gasket.
(2) Lubricate new oil filter gasket with clean
engine oil.
Fig. 78 Oil Level
1 - ENGINE OIL LEVEL DIPSTICK
KJENGINE9s-47
LUBRICATION (Continued)